(1) Field of the Invention
The invention pertains generally to captive portals. More specifically, the invention relates to causing a web browser of a client device to display a designated web page after requesting a requested web page.
(2) Description of the Related Art
The term “captive portal” generally refers to any technique that automatically forces a client device running a web browser to display a specially designated web page before being permitted to access a network such as the Internet in a normal manner.
Captive portals are often utilized in situations where it is required to force new users to view a login portal. For example, before allowing a guest in a hotel to surf the Internet, the guest may be required to log in at the hotel's login portal for billing and/or authentication purposes. Although it is possible to simply instruct users to manually navigate to a special Uniform Resource Locator (URL) or Internet Protocol (IP) address such as by placing instructional cards or brochures near network connection ports in the hotel room, a typical hotel guest would not read these instructions and instead expect the process to be fully automatic. Rather than requiring users to type in the URL or IP address of the login portal, a more user-friendly design presents the user with the login portal regardless of what web site the user may first try to load.
Captive portals typically utilize a well-known browser redirection technique involving hypertext transfer protocol (HTTP) redirect status codes of the form 3xx. To automatically redirect a user's browser to the location of a different web site such as a login portal, the captive portal responds to an HTTP request from the client device with an HTTP response containing a status code 302 and a location field populated with the path of the login portal (e.g., path for the index.html file on the web server hosting the login portal). This HTTP response serves as a browser redirect message indicating to the browser running on the client device that the requested web page has “moved temporarily” to the specified location. In response to the browser redirect message, the web browser automatically redirects itself to the specified location and thereby loads the login portal rather than the originally requested web page.
URL redirection employing the above technique via an intermediate gateway device is described in U.S. Pat. No. 6,636,894 B1, issued Oct. 21, 2003 and entitled, “Systems and methods for redirecting users having transparent computer access to a network using a gateway device having redirection capability”; and U.S. Pat. No. 7,689,716 B2, issued Mar. 30, 2010 and entitled, “Systems and methods for providing dynamic network authorization, authentication and accounting”. Both of these patent documents are incorporated herein by reference.
However, there are some disadvantages associated with the above-described browser redirection approaches. For example, sending a browser redirect message to the user's browser from an intermediate gateway causes the browser's address bar to suddenly jump from the location of the user's requested web page (e.g., URL or IP address) to another location (e.g., a different URL or IP address) that is completely unknown to the user. Some user's may find this behavior alarming because it occurs automatically without their explicit permission. Furthermore, as automatic browser redirection may represent a security risk, browsers often include configurable security measures that when activated display a warning to users when an automatic redirection is attempted. For example, the Firefox™ web browser by Mozilla™ includes a user-configurable security option entitled, “Warn me when web sites try to redirect or reload the page.” With this option enabled, browser redirect messages are blocked and a warning is displayed along the top of the browser window stating, “Firefox prevented this page from automatically redirecting to another page.” To permit the browser redirection to take place, the user must click an “Allow” button in the upper right hand corner. Especially for risk averse and technically unskilled users, these types of browser security measures interfere with the desired functionality of automatically displaying a login portal by a captive portal.